Oats grown with different nutrient treatments in temperature-controlled soil in the greenhouse produced higher yields of grain and straw when soil temperature was increased from 41° to 67°F. Yields were usually less at 80°F. than at 41°F. This relationship between growth and soil temperature was also apparent at the heading stage. At 7th leaf, however, the best temperature for growth varied with nutrient treatment. Root yields usually decreased with increase in soil temperature.Increasing soil temperature from 41° to 67°F. increased uptake of N, P and K. In many instances increases in the concentration of N, P and K in the plant contributed to these increases in uptake. The effect of soil temperature on uptake was more consistent for P than for other elements.Nitrates and native phosphorus in incubated soil samples increased with increase in temperature from 41° to 80°F. but exchangeable K values were not affected.

When grown with different nutrient treatments in temperature‐controlled soil in the greenhouse, yields of corn and bromegrass tops increased with increments in temperature from 41° to 80° F., but yields of potato tops and tubers showed a less consistent relationship with temperature. Yields of corn and bromegrass roots also increased with temperature except for a decline in bromegrass roots when temperature was increased from 67° to 80° F. Tuber yields were usually higher at soil temperatures above 41° F., but the optimum temperature varied with nutrient treatment. The nutrient composition of the crops showed few consistent trends in relation to soil temperature. The P content of bromegrass and potato tops, however, increased with rising temperatures when the plants were grown without added P. Uptake of N, P, Ca, Mg and K by the crops usually increased with increasing temperature to at least 67° F. The uptake of P by the plants without addition of the nutrient, relative to the uptake obtained with addition, increased almost invariably with each increment in temperature. Water‐use efficiency usually increased where N, P and K were added together and often decreased as soil temperatures increased.

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